sql - For autoincrement fields: MAX(ID) vs TOP 1 ID ORDER BY ID DESC

Question

I want to find the highest AutoIncremented value from a field. (its not being fetched after an insert where I can use @@SCOPE_IDENTITY etc) Which of these two queries would run faster or gives better performance. Id is the primary key and autoincrement field for Table1. And this is for Sql Server 2005.

SELECT MAX(Id) FROM Table1

SELECT TOP 1 Id FROM Table1 ORDER BY Id DESC

[Edit]
Yes in this case Id is the field on which I have defined the clustered index.
If the index is ID DESC then what..
And yes it would be nice to know how the performance would be affected if
1. Id is a clustered index + primary key.
2. Id is a clustered index and not primary key.
3. Id is a non clustered index ASC + primary key.
4. Id is a non clustered index ASC and not primary key.
5. Id is a non clustered index DESC + primary key.
6. Id is a non clustered index DESC and not primary key.
7. Id is just AutoIncrement

Hope its not a tall order!

Answer 1

Nobody mentioned IDENT_CURRENT('Table1') - blows them all away - of course it only works on identity columns, but that was the question...